Although there are many types of mascara brushes, in recent years, the most common construction has been the type in which the bristles are secured by a twisted wire core. In a break through advance of a few years ago, the Hartel, et al, U.S. Pat. No. 4,744,425 disclosed and claimed a brush construction which overcame one of the shortcomings of such twisted wire brushes resulting from the tendency of the individual brush filaments to follow the spiral pattern of the twisted wire core. Previously, that construction had left voids or gaps between adjacent convolutions of bristles whereby the mascara product had a tendency to gather and clump therein. The solution found by the inventors Hartel and Sanderson was to provide filaments which were tubular or hollow in cross-section or noncircular so that when such filaments were clamped between the wire turns of the core, the filaments were crimped so as to flare omnidirectionally outward with the result that the filament tips were uniformly distributed. Brushes made and sold by SANDERSON MACLEOD, INC., the assignee of said inventors, and licensees thereof, enjoyed great commercial success.
After the bristle block or head of the mascara brush is formed, the bristles are typically finished by trimming the bristle block to any desirable configuration, such as a cylindrical, conical, polygonal or combinations thereof. Because of the high costs associated with trimming such brush heads, it has not been common practice to produce such brushes in any complex or intricate configurations despite the fact a rectangular brush pattern is considered advantageous in the application of mascara.
Mascara brushes of the type embodying this invention are usually sold to the public as part of a complete mascara package which includes a fluid-type cosmetic disposed therein. The brush extends from a cap and applicator handle and the container typically includes, at its upper end, a diaphragm disposed therein. The diaphragm has a centrally disposed orifice adapted to enable the mascara brush head to pass therethrough to pick up a supply of mascara and to wipe "off" any excess thereof as the brush is withdrawn from the container. The diameter of the orifice is thus made slightly smaller than the outer diameter of the brush head so that when it is withdrawn from the container, the bristles will, in effect, be deflected to ring "out" or squeegee "off" excess fluid from the brush head. The controlled quantity of fluid usually retained by conventional mascara brushes of generally uniform cross-section usually have required numerous reinsertions of the brush into the mascara container to pick up additional mascara.
Many different solutions have been used to overcome the problems of mascara application involving the dual problems of mascara pick up combined with a combing action for uniform application to the eyelashes. In this connection, various combinations of stiffer and softer bristles have been used with some success as has the so-called hollow fiber brush. Nonetheless, the cosmetics' industry is always searching for more effective solutions to the problems of mascara brush performance in a low-cost brush construction.